Support structures for intravascular blood pumps

ABSTRACT

An improved system for supporting (e.g., localization and/or positioning of) intravascular devices discussed herein provides for example a multi-element arrangement. A set of struts optionally projects from the intravascular device and contacts the vessel walls. The localization and positioning of the pump may be provided by the struts and/or by use of a tether opposing a propulsive force to ensure localization.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application claims priority to International Application No.PCT/US2020/064489, filed Dec. 11, 2020, which claims priority to U.S.Provisional Patent Application No. 62/947,940, filed Dec. 13, 2019, theentire contents of which are hereby incorporated by reference herein intheir entirety and for all purposes. This application also claimspriority to International Application No. PCT/US2020/062928, filed Dec.2, 2020, which claims priority to U.S. Provisional Patent ApplicationNo. 62/943,062, filed Dec. 3, 2019, the entire contents of each of whichare hereby incorporated by reference herein in their entirety and forall purposes. Any and all applications for which a foreign or domesticpriority claim is identified in the Application Data Sheet as filed withthe present application are hereby incorporated by reference under 37CFR 1.57.

BACKGROUND Field

The field relates to localization and positioning structures and methodsfor intravascular blood pumps.

Description of the Related Art

In the field of cardiac assist devices and mechanical circulatorysupport, blood pumps are used to support the heart in circulating bloodthrough the body. Some of these blood pumps are intravascular bloodpumps and are designed or adapted for use within blood vessels.

Some intravascular blood pumps have been described as including hooks tofix the intravascular pump to the inner wall of the vessel. Hooksprevent translation of the device along the axis of the vessel androtation of the device about the axis of the vessel through direct localcontact.

SUMMARY OF THE INVENTION

A support or localization structure for a pump that may limit or preventtranslation, limit or prevent rotation, aid in maintaining the positionof some part of the pump relative to some anatomical structure, or anycombination of these is needed. The localization structure may bedesigned for acute, semi-acute, semi-chronic, or chronic use.

Blood is a harsh environment for devices and any thrombus, foreignmaterial, or pathogen in a blood vessel could have dire consequences.Novel localization structures that are biocompatible, non-thrombogenic,and non-hemolytic for well in excess of the expected duration of use areneeded. Additionally, the function and removal of novel means oflocalization should preferentially be consistent with anyendothelialization that may occur during the expected duration of use.

Novel localization structures for intravascular devices preferablyprovide biocompatibility of materials and surfaces, design forhemodynamic compatibility (reduced or minimal flow mediatedthrombogenicity and hemolysis and disruption to natural flow), reducedor minimal trauma to the inside of the vessel or other anatomicalstructures, sufficient localization and freedom of motion, andremovability when the therapy that the localized device provides iscomplete.

Localization and positioning systems and methods for medical devices,such as intravascular blood pumps or other intravascular devices aredisclosed herein. The various embodiments comprise one or more of thefollowing elements: struts extending from the device to be localized,said struts providing constant or intermittent contact with the vesselwall; a tether (e.g., a power lead) to limit translation and aid inpositioning; and propulsion to maintain localization.

In some embodiments, the localization and positioning system may be partof or include a support structure that comprises struts that areprojections that extend distally and radially outward from the device tocontact the blood vessel walls or other anatomical features. Variousillustrated embodiments show the struts extending distal the pumphousing and impeller. However it should be appreciated that,alternatively, any of the struts may instead extend proximal the pumphead (e.g., proximal the motor housing). In such embodiments, one ormore of the struts can extend proximally from the drive unit or shroud.In yet other embodiments, one or more, e.g., a first plurality of strutscan extend distal the pump housing and impeller, and one or more, e.g.,a second plurality of struts can extend proximal the pump head (e.g.,proximal the motor housing). The struts may be shaped, formed, andprocessed so that for a given outward radial force in the expandedconfiguration, the radial force in the collapsed configuration and/orthe force to move from the expanded to collapsed configuration isreduced (e.g., minimized).

Struts may consist of or otherwise be formed from a biocompatible metal,shape memory alloy, or alloy, like nitinol, and may be designed to havea particular shape and/or geometry. Through constant or intermittentcontact with the inner wall of the blood vessel or some other anatomicalfeature, struts can provide localization or positioning or both. Adevice to be positioned may have multiple sets of struts and these mayproject from the device at one or more angles or at any angle. In someembodiments, the struts may have features like hooks. In otherembodiments, the struts may have pads to interface with the surface ofthe blood vessel wall. For use with intravascular devices, struts mayhave a collapsed configuration for fitting within a sheath and anexpanded configuration to provide localization and/or positioning. Insome embodiments the struts may have knees (or kinks or bends) toprevent hooks or other features from contacting the inner wall of asheath in a collapsed configuration. The struts may be shaped, formed,and processed so that for a given outward radial force in the expandedconfiguration, the radial force in the collapsed configuration and/orthe force required to move from the expanded to collapsed configurationis reduced or minimized.

In some embodiments, the localization, stabilization, and positioningsystem (or support structure) may comprise one or more tethers thatconnect the device to be localized and/or positioned to one or moreanchor or contact points. Tethers may be flexible and may preferentiallylimit translation or rotation in one direction. In some embodiments, thetethers may have an additional function. As one nonlimiting example, atether may also comprise a power lead that transmits electrical power tothe device to be localized or positioned.

In some embodiments, the localization, stabilization, and positioningsystem may comprise a means of propulsion (e.g., a pump in variousembodiments). In cases where the device to be localized and/orpositioned is an intravascular blood pump, the pumping of blood is a keyfunction of the device in some embodiments. The propulsive or reactiveforce generated by blood pumping may be used as part of the localizationand positioning system.

In some embodiments, the localization and/or positioning system maycomprise combinations of the above elements that together provide uniquebenefits or advantages.

The discussion herein has outlined rather broadly various features ofthe present disclosure in order that the detailed description thatfollows may be better understood. Additional features and advantages ofthe disclosure will be described hereinafter.

In one embodiment, a blood flow assist system is disclosed. The bloodflow assist system can include or consist essentially of an impellerdisposed in a pump housing of a pump, the pump comprising a longitudinalaxis, the impeller generating a thrust force when operating in a bloodvessel to pump blood; and a tether extending away from the pump housing,the tether configured to oppose loads applied in opposite directions atopposite ends thereof. In some embodiments, a longitudinal component ofthe thrust force generated by the impeller directed along thelongitudinal axis of the pump is opposed by the tether, the tetherconfigured to maintain a position of the pump within the blood vesselwithout requiring contact between the pump and a blood vessel wall ofthe blood vessel.

In some embodiments, the system includes a support structure coupled toor formed with the pump housing, the support structure configured to atleast intermittently contact the blood vessel wall to maintain spacingof the pump housing from the blood vessel wall in which the pump housingis disposed. In some embodiments, the support structure comprises aplurality of elongate struts having a first end coupled with the pumphousing and a second end opposite the first end, each elongate strut ofthe plurality of struts having a slender body and extending between thefirst end and the second end. In some embodiments, the system includesconvex contact pads disposed at respective distal portions of theplurality of struts, the convex contact pads configured to at leastintermittently contact the blood vessel wall to maintain spacing of thepump housing from a blood vessel wall in which the pump housing isdisposed. In some embodiments, the plurality of struts includes a firstplurality of struts and a second plurality of struts, wherein, when theplurality of struts are in an expanded configuration, first contact padsof the first plurality of struts are configured to engage with the bloodvessel wall at a first longitudinal position and second contact pads ofthe second plurality of struts are configured to engage with the bloodvessel wall at a second longitudinal position that is spaced from thefirst longitudinal position. In some embodiments, the contact pads areconfigured to be disposed distal and radially outward of the pumphousing and to be reversibly deflectable to hold the pump housing withinthe blood vessel to hold the pump housing away from the blood vesselwall. In some embodiments, the contact pads comprise a convex peripherysurrounding a convex blood vessel engagement surface. In someembodiments, the contact pads comprise a convex profile in across-sectional plane disposed transverse to a longitudinal axis of thepump. In some embodiments, the tether comprises a conductor configuredto convey current to a motor operatively coupled to the impeller from asource connectable to a proximal end of the tether. In some embodiments,the system includes the pump further comprises a motor housing coupledto a proximal portion of the pump housing, the motor disposed in themotor housing. In some embodiments, the tether comprises a rotatabledrive shaft connected to a motor to be disposed outside a body of thepatient. In some embodiments, a kit comprises the blood flow assistsystem and a sheath sized and shaped to receive the pump housing, thetether, and the support structure.

In another embodiment, a blood flow assist system is disclosed. Theblood flow assist system can include or consist essentially of animpeller disposed in a pump housing of a pump, the pump comprising alongitudinal axis, the impeller generating a thrust force when operatingin a blood vessel to pump blood; a tether extending away from the pumphousing, the tether configured to oppose loads applied in oppositedirections at opposite ends thereof; and a support structure.

In some embodiments, the support structure comprises convex contact padsconfigured to at least intermittently contact a blood vessel wall tomaintain spacing of the pump housing from a blood vessel wall in whichthe pump housing is disposed. In some embodiments, the system caninclude a motor operatively coupled with the impeller. In someembodiments, the tether comprises a hollow, elongate member enclosing aconductor disposed therein, the conductor configured to convey currentto and from the motor from a source connectable to a proximal end of thetether, the tether configured to oppose loads applied in oppositedirections at opposites ends thereof. In some embodiments, the systemincludes a plurality of elongate struts having a first end coupled witha second end of the pump and a second end opposite the first end, eachelongate strut of the plurality of elongate struts comprising a slenderbody extending between the first end and the second end, each strut ofthe plurality of elongate struts being configured to store strain energywhen a transverse load is applied. In some embodiments, the blood flowassist system includes a contact pad disposed at the second end of eachof the elongate struts of the plurality of elongate struts, each contactpad having an enlarged width compared to a width of the immediatelyadjacent expanse of the corresponding elongate strut of the plurality ofelongate struts. In some embodiments, in use, a longitudinal componentof the thrust force generated by the impeller directed along thelongitudinal axis of the pump is opposed by the tension member of thetether.

In some embodiments, the contact pad comprises a generally circular padhaving a diameter greater than the width of the immediately adjacentexpanse of the corresponding elongate struts. In some embodiments, theelongate struts comprise at least one inflection along the slender bodythereof to facilitate folding of the struts into a lumen of a sheath. Insome embodiments, each of the contact pads comprises a smooth surfacefree of sharp edges or hooks. In some embodiments, each of the contactpads comprises a convex cross-sectional profile on a blood vessel facingside thereof. In some embodiments, each of the contact pads comprises aspherical portion. In some embodiments, the elongate struts areconfigured to apply a load to an aortic wall when deployed to locallyradially expand vessel wall tissue against which the contact pad isapposed. In some embodiments, the contact pad comprises a holeconfigured to allow blood vessel wall tissue to be received therein. Insome embodiments, each of the contact pads comprises one or morescalloped edges to allow blood vessel wall tissue to be receivedtherein. In some embodiments, each of the contact pads comprises a domedportion. In some embodiments, the hollow, elongate member is configuredto receive a stiffening member to facilitate introduction of the pumphousing. In some embodiments, the pump further comprises a motor housingcoupled to a proximal portion of the pump housing, the motor disposed inthe motor housing. In some embodiments, a transverse component of thethrust force directed transverse to the longitudinal axis of the pump isopposed by strain energy stored in at least one of the elongate strutsof the plurality of elongate struts upon deflection of one or more ofthe elongate struts of the plurality of struts. In some embodiments, akit comprises the blood flow assist system and a sheath sized and shapedto receive the pump housing, the motor, the tether, and the plurality ofelongate struts.

In some embodiments, the support structure comprises a plurality ofelongate struts having a first end coupled with a second end of the pumpand a second end opposite the first end, each elongate strut of theplurality of struts having a slender body and extending between thefirst end and the second end, the convex contact pads disposed atrespective distal portions of the plurality of struts. In someembodiments, the plurality of struts includes a first plurality ofstruts and a second plurality of struts, wherein, when the plurality ofstruts are in an expanded configuration, first contact pads of the firstplurality of struts are configured to engage with the blood vessel wallat a first longitudinal position and second contact pads of the secondplurality of struts are configured to engage with the blood vessel wallat a second longitudinal position that is spaced from the firstlongitudinal position. In some embodiments, in a collapsed configurationof the struts, at least a portion of the struts has a major lateraldimension that is no more than a major lateral dimension of the pumphousing. In some embodiments, the contact pads are configured to bedisposed distal and radially outward of the pump housing and to bereversibly deflectable to hold the pump housing within the blood vesselto hold the pump housing away from the blood vessel wall. In someembodiments, the contact pads comprise a convex periphery surrounding aconvex blood vessel engagement surface. In some embodiments, the contactpads comprise a convex profile in a cross-sectional plane disposedtransverse to a longitudinal axis of the pump. In some embodiments, thetether comprises a conductor configured to convey current to a motoroperatively coupled to the impeller from a source connectable to aproximal end of the tether. In some embodiments, the pump furthercomprises a motor housing coupled to a proximal portion of the pumphousing, the motor disposed in the motor housing. In some embodiments,the tether comprises a rotatable drive shaft connected to a motor to bedisposed outside a body of the patient.

In another embodiment, a blood flow assist system is disclosed. Theblood flow assist system can include or consist essentially of animpeller disposed in a pump housing of a pump; and a support structurecomprising a plurality of struts coupled to or formed with the pumphousing, the support structure having an expanded configuration in whichthe plurality of struts extend outwardly relative to the pump housingand a collapsed configuration in which the pump is disposed in a sheath,wherein, in the collapsed configuration, at least a portion of thestruts has a major lateral dimension that is no more than a majorlateral dimension of the pump housing. In some embodiments, the majorlateral dimension of the at least the portion of the struts is less thanthe major lateral dimension of the pump housing. In some embodiments,the blood flow assist system includes a motor housing and a motordisposed in the motor housing, wherein the major lateral dimension ofthe at least the portion of the struts is less than a major lateraldimension of the motor housing. In some embodiments, the blood flowassist system includes convex contact pads at a distal portion of thestruts, the convex contact pads configured to contact a blood vesselwall to maintain spacing of the pump housing from a blood vessel wall inwhich the pump housing is disposed.

In another embodiment, a blood flow assist system is disclosed. Theblood flow assist system can include or consist essentially of animpeller disposed in a pump housing of a pump; and a support structurecomprising a plurality of struts coupled to or formed with the pumphousing, the support structure having an expanded configuration in whichthe plurality of struts extend outwardly relative to the pump housingand a collapsed configuration in which the pump is disposed in a sheath,wherein the plurality of struts includes a first plurality of struts anda second plurality of struts, wherein, when the plurality of struts arein an expanded configuration, first contact pads of the first pluralityof struts are configured to engage with the blood vessel wall at a firstlongitudinal position and second contact pads of the second plurality ofstruts are configured to engage with the blood vessel wall at a secondlongitudinal position that is spaced from the first longitudinalposition. In some embodiments, the blood flow assist system includesconvex contact pads at a distal portion of the plurality of struts, theconvex contact pads configured to at least intermittently contact ablood vessel wall to maintain spacing of the pump housing from a bloodvessel wall in which the pump housing is disposed. In some embodiments,a major lateral dimension of the at least a portion of the struts isless than a major lateral dimension of the pump housing. In someembodiments, the blood flow assist system includes a tether extendingaway from the pump housing, the tether configured to oppose loadsapplied in opposite directions at opposite ends thereof.

In another embodiment, a blood flow assist system is disclosed. Theblood flow assist system can include or consist essentially of animpeller disposed in a pump housing of a pump, the pump comprising alongitudinal axis, the impeller generating a thrust force when operatingin a blood vessel to pump blood; a tether coupled with a first end ofthe pump; and a support structure comprising a contact pad resilientlydeflectable toward and away from a longitudinal axis of the pump, a freestate of the contact pad being spaced away from the longitudinal axis ofthe pump by a distance greater than a half-width of a blood vessel intowhich the pump housing is to be deployed, the contact pad applyingsufficient force to a wall of the blood vessel to depress a portion ofthe contact pad into the wall such that a surrounding portion of thevessel wall is radially inward from a contact surface of the contactpad. In some embodiments, the contact pad is configured to engagewithout hooking the wall of the blood vessel when applied. In someembodiments, the contact pad comprises an elongate member and anenlarged blood vessel wall contact surface disposed at the end of theelongate member. In some embodiments, the tether comprises a conductorconfigured to convey current from a source connectable to a proximal endof the tether to a motor operatively coupled with the impeller.

In another embodiment, a blood flow assist system is disclosed. Theblood flow assist system can include or consist essentially of a pumpcomprising: an impeller disposed in a pump housing; and a strutcomprising a first end disposed at or coupled with the pump housing, asecond end opposite the first end, and an inflection zone disposedbetween the first end and the second end, the second end elasticallydeflectable toward and away from a longitudinal axis of the pump, a freestate of the strut spacing the second end thereof away from thelongitudinal axis of the pump, the second end of the strut configured toengage a wall of the blood vessel. The system can include or consistessentially of a sheath comprising an inner wall configured to bedisposed over the pump and to deflect the strut between the first andthe second end thereof; wherein the inflection zone is configured suchthat when the strut is deflected by the inner wall of the sheath, thesecond end of the strut is spaced away from the inner wall of thesheath. In some embodiments, the second end of the strut comprises ahook. In some embodiments, the inflection zone comprises an S-connectionbetween a first span of the strut and a second span of the strut, thefirst span and the second span being disposed along paralleltrajectories. In some embodiments, the blood flow assist system includesa tether coupled with a first end of the pump, the tether comprising anelectrical conveyance comprising a conductor configured to conveycurrent to and from a source connectable to a proximal end of theelectrical conveyance.

In another embodiment, a method of operating a blood flow assist system.The method can include or consist essentially of providing a pump at atreatment location within a blood vessel of a patient, the pumpincluding a pump housing disposed in a sheath, an impeller disposed inthe pump housing, and a plurality of elongate struts extending from thepump housing in a collapsed configuration, each elongate strut of theplurality of struts including a convex contact pad at a distal endthereof; providing relative motion between the sheath and the pump toremove the pump from the sheath, the plurality of elongate strutsradially self-expanding to an expanded configuration in which at leastone convex contact pad at least intermittently makes contact with avessel wall of the blood vessel to maintain spacing of the pump from thevessel wall; and rotating the impeller to pump blood. In someembodiments, the method includes conveying electrical current to a motorby way of a tether comprising a conductor, the motor operatively coupledwith the impeller and the tether coupled to the pump, wherein rotatingthe impeller generates a thrust force, the tether opposing the thrushforce. In some embodiments, the method includes percutaneouslydelivering the sheath to the treatment location, and, subsequently,delivering the pump to the treatment location. In some embodiments, themethod includes causing a portion of the contact pad to depress into thevessel wall. In some embodiments, the method includes removing the pumpfrom the patient.

In another embodiment, a method of operating a blood flow assist systemis disclosed. The method can include or consist essentially of providinga pump at a treatment location within a blood vessel of a patient, thepump including a pump housing disposed in a sheath, an impeller disposedin the pump housing, and a plurality of elongate struts extendingdistally from the pump housing in a collapsed configuration; providingrelative motion between the sheath and the pump to remove the pump fromthe sheath, the plurality of elongate struts radially self-expanding toan expanded configuration in which at least one contact pad at an end ofat least one strut of the plurality of elongate struts at leastintermittently makes contact with a vessel wall of the blood vessel tomaintain spacing of the pump from the vessel wall, the at least onecontact pad applying sufficient force to the vessel wall of the bloodvessel to depress a portion of the contact pad into the vessel wall suchthat a surrounding portion of the vessel wall is radially inward fromthe contact pad; and rotating the impeller to pump blood. In someembodiments, the method includes percutaneously delivering the sheath tothe treatment location, and, subsequently, delivering the pump to thetreatment location. In some embodiments, the method includes removingthe pump from the patient. In some embodiments, the method includesconveying electrical current to a motor by way of a tether comprising aconductor, the motor operatively coupled with the impeller and thetether coupled to the pump.

In another embodiment, a method of manufacturing a blood flow assistsystem is disclosed. The method can include or consist essentially ofproviding an impeller in a pump housing of a pump, the pump disposedalong a longitudinal axis, the impeller generating a thrust force whenoperating in a blood vessel to pump blood; coupling a tether with afirst end of the pump; and coupling a support structure to a second endof the pump, the support structure comprising convex contact padsconfigured to at least intermittently contact a blood vessel wall tomaintain spacing of the pump housing from a blood vessel wall in whichthe pump housing is disposed. In some embodiments, the method includesproviding the motor in a motor housing of the pump, the motor housingdisposed distal the pump housing. In some embodiments, the supportstructure comprises a plurality of elongate struts having a first endcoupled with the second end of the pump and a second end opposite thefirst end, each elongate strut of the plurality of struts having aslender body and extending between the first end and the second end,each strut of the plurality of elongate struts being configured to storestrain energy when a transverse load is applied to the second ends ofthe struts of the plurality of elongate struts. In some embodiments, themethod includes patterning the plurality of elongate struts. In someembodiments, patterning comprises laser cutting the plurality ofelongate struts from a sheet of material.

In another embodiment, a method of operating a blood flow assist systemis disclosed. The method can include or consist essentially of providinga pump at a treatment location within a blood vessel of a patient, thepump including a pump housing disposed in a sheath, an impeller disposedin the pump housing, and a tether extending proximally from the pumphousing to outside the patient, the tether configured to oppose loadsapplied in opposite directions at opposite ends thereof; providingrelative motion between the sheath and the pump to remove the pump fromthe sheath; rotating the impeller to pump blood and to generate a thrustforce, wherein a longitudinal component of the thrust force generated bythe impeller directed along a longitudinal axis of the pump is opposedby the tether, the tether configured to maintain a position of the pumpwithin the blood vessel without requiring contact between the pump and ablood vessel wall of the blood vessel. In some embodiments, the pumpincludes a plurality of elongate struts extending distally from the pumphousing in a collapsed configuration, each elongate strut of theplurality of struts including a convex contact pad at a distal endthereof, wherein providing relative motion comprises causing theplurality of elongate struts to radially self-expand to an expandedconfiguration in which at least one convex contact pad makes at leastintermittent contact with a vessel wall of the blood vessel to maintainspacing of the pump from the vessel wall.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended for illustrativepurposes and should in no way be interpreted as limiting the scope ofthe embodiments. Furthermore, various features of different disclosedembodiments can be combined to form additional embodiments, which arepart of this disclosure. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments. The following is a brief description of each of thedrawings.

FIG. 1A is a schematic perspective, partially-exploded view of a bloodflow assist system, according to various embodiments.

FIG. 1B is a schematic perspective view of a pump at a distal portion ofthe blood flow assist system of FIG. 1A.

FIG. 1C is a schematic perspective, partially-exploded view of the pumpof FIG. 1B.

FIG. 1D is a schematic side sectional view of a motor housing accordingto various embodiments.

FIG. 1E is a schematic perspective view of a motor and a motor mountsupport.

FIG. 1F is a schematic perspective view of a distal end of a power leadhaving lumens shaped to received conductors that are configured tosupply power to the motor.

FIG. 1G is a schematic perspective view of a proximal end portion of thepower lead.

FIG. 1H is a schematic side view of the pump disposed in a collapsedconfiguration in a delivery sheath.

FIG. 1I is a schematic perspective view of a retrieval feature used toremove the pump, according to some embodiments.

FIG. 1J is a cross-sectional view of an alternative embodiment in whicha drive shaft is coupled to a motor configured to be disposed outsidethe patient when the pump is in use.

FIG. 2A is an image showing a front perspective view of a localizationsystem, according to one embodiment.

FIG. 2B is a schematic side view of the localization system of FIG. 2A.

FIG. 2C is a schematic plan view of a laser cut pattern for thelocalization system of FIG. 2B.

FIG. 2D is a schematic side plan view of a strut having a dome- orspherical-shaped contact pad.

FIG. 2E is a schematic perspective view of a contact pad that pillowsinto a blood vessel wall, according to some embodiments.

FIG. 2F is a schematic front sectional view of the contact pad shown inFIG. 2E.

FIG. 2G is a schematic side sectional view of the contact pad shown inFIG. 2E.

FIG. 3A is an image of a front perspective of a localization systemaccording to another embodiment.

FIG. 3B is an image of a side view of the localization system of FIG.3A.

FIG. 3C is a schematic side view of the localization system of FIGS.3A-3B.

FIG. 3D is a schematic enlarged view of the second end of the strut ofFIGS. 3A-3C.

FIGS. 3E and 3F are schematic plan views of the localization system in alaser cut pattern prior to assembly.

FIG. 3G illustrates a plan view of a distal end of the strut of FIG. 3D.

FIGS. 4A-4E show a method of delivering and deploying a localization andpositioning system that incorporates struts with contact pads, a tether,and propulsive force.

FIG. 5A is a schematic perspective view of a localization system in acollapsed configuration, according to another embodiment.

FIG. 5B is a schematic plan view of a laser cut design for the system ofFIG. 5A.

FIG. 6 is a schematic side view of a plurality of struts according tovarious embodiments.

DETAILED DESCRIPTION

Refer now to the drawings wherein depicted elements are not necessarilyshown to scale and wherein like or similar elements are designated bythe same reference numeral through the several views.

Referring to the drawings in general, it will be understood that theillustrations are for the purpose of describing particularimplementations of the disclosure and are not intended to be limitingthereto. While most of the terms used herein will be recognizable tothose of ordinary skill in the art, it should be understood that whennot explicitly defined, terms should be interpreted as adopting ameaning presently accepted by those of ordinary skill in the art.

I. Overview of Blood Flow Assist Systems

Various embodiments disclosed herein relate to a blood flow assistsystem 1 configured to provide circulatory support to a patient, asillustrated in FIGS. 1A-1I. The system 1 can be sized for intravasculardelivery to a treatment location within the circulatory system of thepatient, e.g., to a location within the descending aorta of the patient.As shown in FIG. 1A, the system 1 can have a proximal end 21 with aconnector 23 configured to connect to an external control system, e.g.,a console (not shown). The connector 23 can provide electricalcommunication between the control system and a power lead 20 extendingdistally along a longitudinal axis L from the connector 23 and theproximal end 21. The power lead 20 can comprise an elongate body thatelectrically and mechanically connects to a pump 2 at or near a distalend 22 of the blood flow assist system 1, with the distal end 22 spacedapart from the proximal end 21 along the longitudinal axis L. Asexplained herein, the power lead 20 can also serve as a flexible tetherconfigured to oppose loads applied in opposite directions at oppositeends of the power lead 20.

The pump 2 can comprise a pump head 50 including a pump housing 35connected to a drive unit 9 that includes a motor housing 29. Aretrieval feature 48 can be provided at a proximal end portion of thepump 2. In some embodiments, the retrieval feature can be coupled withthe distal end of the power lead 20 between the power lead 20 and themotor housing 29. After a procedure, the clinician can remove the pump 2from the patient by engaging a tool (e.g., a snare, a clamp, hook, etc.)with the retrieval feature 48 to pull the pump 2 from the patient. Forexample, the retrieval feature 48 can comprise a neck 49 (e.g., areduced diameter section) at a proximal curved portion 51 c of the motorhousing 29 and an enlarged diameter section disposed proximal the neck49. The enlarged diameter section can comprise a first curved portion 51a and a second curved portion 51 b, as shown in FIGS. 1B, 1C, and 1I.The first and second curved portions 51 a, 51 b can comprise convexsurfaces, e.g., convex ball portions. The first and second curvedportions 51 a, 51 b can have different radii of curvature. For example,as shown in FIG. 1I, the first curved portion 51 a can have a largerradius of curvature than the second curved portion 51 b. The firstcurved portion 51 a can be disposed on opposing sides of the retrievalfeature 48 in some embodiments. The second curved portion 51 b can bedisposed around the first curved portion 51 a and can have aradially-outward facing surface and a proximally-facing convex surfacecoupled to the distal end of the power lead 20. The neck 49 can have afirst depth at a first circumferential position of the retrieval feature48 and a second depth less than the first depth at a secondcircumferential position of the retrieval feature 48 spaced apart fromthe first circumferential position.

Beneficially, as shown in FIG. 1I, one or more first planes P1 extendingparallel to the longitudinal axis L and intersecting the first curvedportion 51 a can have a first angle or taper between the proximal curvedportion 51 c of the motor housing 29 and the first curved portion 51 a.One or more second planes P2 extending parallel to the longitudinal axisL and intersecting the second curved portion 51 b can have a secondangle or taper (which is different from the first angle or taper)between the proximal curved portion 51 c of the motor housing 29 and thesecond curved portion 51 b. The first angle or taper can provide agradual, continuous (generally monotonically decreasing) geometrictransition between the proximal curved portion 51 c of the motor housing29 and the power lead 20, which can provide for smooth blood flow andreduce the risk of thrombosis. The second curved portion 51 b can serveas a lobe that extends radially outward, e.g., radially farther out thanthe first curved portion 51 a. The second curved portion 51 b can beused to engage with a retrieval device or snare to remove the pump 2from the anatomy. Some cross sections through the longitudinal axis ofthe retrieval feature 48 can contain a substantial neck (e.g., a localminimum in the radius of curvature measured along its central axis)while other cross sections through the longitudinal axis of theretrieval feature 48 can contain an insubstantial local minimum or nolocal minimum. In the illustrated embodiment, there are two first curvedportions 51 a that can serve as a dual lobe retrieval feature. In otherembodiments, more or fewer lobes can be provided to enable pumpretrieval while ensuring smooth flow transitions between the motorhousing 29 and power lead 20.

As shown in FIGS. 1B-1C, 1E, and 1I, the neck 49 can be disposed betweenthe curved portions 51 a, 51 b and a proximally-facing convex surface 51c of the motor housing 29. In the illustrated embodiment, the retrievalfeature 48 can be coupled to or integrally formed with the motor housing29. In other arrangements, the retrieval feature 48 can be disposed atother locations of the pump 2. As shown, the retrieval feature 48 can besymmetrical and continuously disposed about the longitudinal axis L. Inother arrangements, the retrieval feature 48 can comprise a plurality ofdiscrete surfaces spaced apart circumferentially and/or longitudinally.In the illustrated embodiments, the motor housing 29 (and motor) can bepart of the pump 2 and disposed inside the vasculature of the patient inuse. In other embodiments, however, the motor housing 29 (and motor) canbe disposed outside the patient and a drive cable can connect to theimpeller 6.

As shown in FIGS. 1A-1C, the drive unit 9 can be configured to impartrotation to an impeller assembly 4 disposed in the pump housing 35 ofthe pump head 50. As explained herein, the drive unit 9 can include adrive magnet 17 (see FIG. 1D) and a motor 30 (see FIGS. 1D-1E) disposedin the motor housing 29 capped by a distal drive unit cover 11. Themotor 30 is shown schematically in FIG. 1D. The drive unit cover 11 canbe formed with or coupled to a drive bearing 18. The drive magnet 17 canmagnetically couple with a corresponding driven or rotor magnet (notshown) of the impeller assembly 4 that is disposed proximal the impeller6 within the shroud 16. The power lead 20 can extend from the treatmentlocation to outside the body of the patient, and can provide electricalpower (e.g., electrical current) and/or control to the motor 30.Accordingly, no spinning drive shaft extends outside the body of thepatient in some embodiments. As explained herein, the power lead 20 canenergize the motor 30, which can cause the drive magnet 17 to rotateabout the longitudinal axis L, which can serve as or be aligned with orcorrespond to an axis of rotation. Rotation of the drive magnet 17 canimpart rotation of the rotor magnet and a primary or first impeller 6 ofthe impeller assembly 4 about the longitudinal axis L. For example, asexplained herein, the rotor magnet (which can be mechanically secure toan impeller shaft 5) can cause the impeller shaft 5 (which can serve asa flow tube) and the first impeller 6 to rotate to pump blood. In otherembodiments, the drive unit 9 can comprise a stator or other stationarymagnetic device. The stator or other magnetic device can be energized,e.g., with alternating current, to impart rotation to the rotor magnet.In the illustrated embodiments, the impeller 6 can have one or aplurality of blades 40 extending radially outward along a radial axis Rthat is radially transverse to the longitudinal axis L. For example, thefirst impeller 6 can have a plurality of (e.g., two)longitudinally-aligned blades 40 that extend radially outwardly from acommon hub and that have a common length along the longitudinal axis L.The curvature and/or overall profile can be selected so as to improveflow rate and reduce shear stresses. Skilled artisans would appreciatethat other designs for the first impeller 5 may be suitable.

As shown in FIGS. 1A-1C, the impeller assembly 4 can be disposed in ashroud 16. The impeller shaft 5 can be supported at a distal end by asleeve bearing 15 connected to a distal portion of the shroud 16. Asupport structure such as a localization system 100 (discussed furtherbelow) can comprise a base portion 36 coupled with the sleeve bearing 15and/or the shroud 16. In some embodiments, the base portion 36, thesleeve bearing 15, and/or the shroud 16 can be welded together. In otherembodiments, the sleeve bearing 15 and/or the shroud 16 can be formed asone part. The base portion 36 of the support structure or localizationsystem 100 (which can be part of or serve as a support structure), thesleeve bearing 15, and the shroud 16 can cooperate to at least partiallydefine the pump housing 35, as shown in FIGS. 1A and 1C. Thelocalization system 100 can comprise a plurality of self-expandingstruts 19 having convex contact pads 24 configured to contact a bloodvessel wall to maintain spacing of the pump housing 35 from the wall ofthe blood vessel in which the pump housing 35 is disposed. In FIGS.1A-1C, the struts 19 of the localization system 100 are illustrated inan expanded, deployed configuration, in which the contact pads 24 extendradially outward to a position in which the contact pads 24 wouldcontact a wall of a blood vessel within which the pump 2 is disposed toat least partially control position and/or orientation of the pump head50 relative to the blood vessel wall, e.g., to anchor, the pump 2 duringoperation of the system 1.

A first fluid port 27 can be provided distal the impeller assembly 4 ata distal end of the pump housing 35. The shroud 16 can comprise aproximal ring 26 coupled with the motor housing 29 and a plurality ofsecond fluid ports 25 formed in a proximal portion of the shroud 16adjacent (e.g., immediately distal) the proximal ring 26. As shown inFIG. 1C, the second fluid ports 25 can comprise openings formed betweenaxially-extending members 60 (also referred to as pillars) that extendalong the longitudinal axis L (which may also serve as a longitudinalaxis of the pump head 2 and/or pump housing 35) between the proximalring 26 and a cylindrical section 59 of the shroud 16. In someembodiments, the axially-extending members 60 can be shaped or otherwisebe configured to serve as vanes that can shape or direct the flow ofblood through the second fluid ports 25. For example, in variousembodiments, the axially-extending members 60 can be angled, tapered, orcurved (e.g., in a helical pattern) to match the profile of the impellerblades 40 and/or to accelerate blood flow through the pump 2. In otherembodiments, the axially-extending members 60 may not be angled to matchthe blades 40. In some embodiments, the first fluid port 27 can comprisean inlet port into which blood flows. In such embodiments, the impellerassembly 4 can draw blood into the first fluid port 27 and can expel theblood out of the pump 2 through the second fluid ports 25, which canserve as outlet ports. In other embodiments, however, the direction ofblood flow may be reversed, in which case the second fluid ports 25 mayserve as fluid inlets and the first fluid port 27 may serve as a fluidoutlet.

As shown in FIGS. 1A-1D, the system 1 comprises the drive unit 9 withthe motor 30 that can be sealed in the motor housing 29. The drivemagnet 17 can be rotatable by the motor 30 by way of a motor shaft 51.The motor 30 can electrically connect to the power lead 20. The powerlead 20 can serve as a flexible tether that comprises an elongatetension member configured to oppose loads applied in opposite directs atopposite ends of the power lead 20. In one embodiment the power lead 20is hollow, as discussed further below. As shown in FIGS. 1D and 1F, thepower lead 20 can comprise an insulating body having a central lumen 55and a plurality of (e.g., three) outer lumens 56A-56C extending along alength of the power lead 20. One or more electrical conductors can bedisposed in the hollow elongate power lead 20 and can be configured toconvey current to the motor 30 from a source, such as the externalcontrol system. For example, in some embodiments, the outer lumens56A-56C can be sized and shaped to receive corresponding electrodes orelectrical wires (not shown) to provide electrical power to the motor30. For example, the lumens 56A-56C can receive, wires configured tosupply ground and drive voltage to corresponding windings on the motor.The electrodes can extend through corresponding openings 57A-57C of amotor mounting support 54 configured to support the motor 30. Thecentral lumen 55 can be sized and shaped to receive an elongatestiffening member or guidewire (not shown). The stiffening member orguidewire can be inserted through an opening 65 at the proximal end 21(see FIG. 1G) into the central lumen 55 during delivery to help guidethe pump 2 to the treatment location or maintain the pump 2 in a givenlocation. The stiffening member or guidewire can be easily inserted andremoved when finished. As shown in FIG. 1G, the connector 23 near theproximal end 21 of the system 1 can have electrical contacts 58A-58Celectrically connected to the wires or conductors in the correspondingouter lumens 56A-56C. The contacts 58A-58C can comprise rings spacedapart by an insulating material and can be configured to electricallyconnect to corresponding electrical components in the control system orconsole (not shown).

Beneficially, the blood flow assist system 1 can be deliveredpercutaneously to a treatment location in the patient. FIG. 1H shows thepump 2 disposed within an elongate sheath 28. As shown, the struts 19are held in a collapsed configuration by the inner wall of the sheath28. As discussed further below, the struts 19 can be configured tocollapse in a controlled manner, e.g., with at least a portion deflectedaway from inner wall of the sheath 28 when disposed in the sheath. Asshown, the struts 19 can comprise knees 102, which can serve to spacedistal ends of the struts 19 (e.g., at or near the contact pads 24 orhooks) from the inner wall of the sheath 28, such that there is a space46 between the contact pads 24 or hooks and the inner wall of the sheath28 in the collapsed configuration within the sheath 28.

The knees 102 can be of the same configuration for each of the struts 19in one embodiment. In such an embodiment, the struts 19 may all collapseor fold in the same manner within the sheath 28. In another embodimentthe knee 102 of one or more struts 19 can be differentiated from theknee 102 of one or more other struts 19 such that the struts arecollapsed or folded in different manners. As explained herein, invarious embodiments, the struts can be longitudinally-aligned orlongitudinally-offset or staggered. For example, a pair of opposingstruts 19 (e.g., disposed radially opposite one another) can have knees102 that cause the opposing strut of the pair to collapse prior to thecollapsing of other struts 19 of the pump 2. In one example, the pump 2has four struts 19. Two opposing struts 19 are configured to bend at theknees 102 prior to the bending of the knees of the other struts 19. Assuch, the two opposing struts 19 can be collapsed to a position betweenthe other two struts to provide a compact arrangement. The knees 102 canbe configured such that some struts undergo a greater degree of bendingor collapsing. Thus the space 46 between the contact pads 26 and theinner wall of the sheath 28 can be two to six (and in some cases threeto four) times greater for one or more, e.g., a pair of, struts than forone or more, e.g., another pair of struts 19, which can be provided toavoid tangling of the struts. Accordingly, in various embodiments, somestruts may be structured to collapse first when engaged with the sheath28, and the remaining struts can collapse as the sheath 28 induces thecollapsing of the initial struts.

In some embodiments, one or more struts comprises knees 102 that cancontrol the order of collapsing of the struts. For example one or morestruts can have a knee 102 positioned more proximally compared to theposition of the knees 102 of one or more other struts. In one example,two opposing struts 19 can have knees 102 disposed more proximally thanare the knees 102 of another strut 19. In one example, a first set ofopposing struts 19 have knees 102 disposed more proximally than a secondset of struts 19 disposed approximately 90 degrees offset from the firstset of struts 19. This can allow the first set of struts to be morecompletely folded by distal advancement of the sheath 28 before a morecomplete folding of the second set of struts 19. In a further variation,knees 102 can be longitudinally spaced apart on adjacent struts 19 sothat adjacent struts fold at different times or rates. The illustratedembodiments includes the knees 102, but in other embodiments, no kneesmay be provided. For example, the struts 19 can be retracted atdifferent rates by hinges and/or by modifying material thickness orproperties in or along the length of one or more struts 19 to controlthe timing or rate of folding upon advancing the sheath 28. A livinghinge structure can be formed along the length of one or more struts 19to control timing, rate, and/or sequence of retraction of the struts 19.In one example, an area of reduced thickness transverse to the length ofa strut 19 causes the strut to fold or bend when a sheath is advancedacross the reduced thickness area. By offsetting the longitudinalposition of reduced thickness areas in the struts 19, the sequence ofretraction can be controlled.

In the collapsed configuration, the struts 19 can be compressed to adiameter or major lateral dimension at one or more locations that isapproximately the same as (or slightly smaller than) the diameter of theshroud 16. Thus, as shown in the collapsed configuration of FIG. 1H, atleast a portion of the struts 19 are compressed to a diameter or majorlateral dimension that is smaller than the major lateral dimension ordiameter of the pump housing 35, shroud 16 and/or the drive unit 9. Insome embodiments, at least a portion of the struts has a major lateraldimension that is no more than a major lateral dimension of the pumphousing 35. In some embodiments, at least a portion of the struts has amajor lateral dimension that is less than a major lateral dimension ofthe pump housing 35 and/or the motor housing 29. The patient can beprepared for the procedure in a catheterization lab in a standardfashion, and the femoral artery can be accessed percutaneously or by asurgical approach. The sheath 28 (or a dilator structure within thesheath 28) can be passed over a guidewire and placed into the treatmentlocation, for example, in the descending aorta. After the sheath 28 isplaced (and the dilator removed), the pump 2 can be advanced into thesheath 28, with the pump 2 disposed in the mid-thoracic aorta,approximately 4 cm below the take-off of the left subclavian artery. Inother embodiments, the pump 2 and sheath 28 can be advanced together tothe treatment location. Positioning the pump 2 at this location canbeneficially enable sufficient cardiac support as well as increasedperfusion of other organs such as the kidneys. Once at the treatmentlocation, relative motion can be provided between the sheath 28 and thepump 2 (e.g., the sheath 28 can be retracted relative to the pump 2, orthe pump 2 can be advanced out of the sheath 28). The struts 19 of thelocalization system can self-expand radially outwardly along the radialaxis R due to stored strain energy into the deployed and expandedconfiguration shown in FIGS. 1A-1C. In some embodiments, such as thosein which the vasculature is accessed by the femoral artery, the struts19 can extend distally, e.g., distally beyond a distal end of the shroud16 and/or the impeller 6. In other embodiments, as explained herein, thepump 2 can be delivered percutaneously through a subclavian artery. Insuch embodiments, the struts 19 may extend proximally, e.g., proximalthe pump housing 35 and/or the motor housing 29. In still otherembodiments, multiple pluralities of struts may extend proximally anddistally relative to the pump 2. The convex contact pads 24 can engagethe blood vessel wall to stabilize (e.g., assist in anchoring) the pump2 in the patient's vascular system. Once at the treatment location, theclinician can engage the control system to activate the motor 30 torotate the impeller assembly 4 to pump blood.

Thus, in some embodiments, the pump 2 can be inserted into the femoralartery and advanced to the desired treatment location in the descendingaorta. In such arrangements, the pump 2 can be positioned such that thedistal end 22 is upstream of the impeller 6, e.g., such that thedistally-located first fluid port 27 is upstream of the second fluidport(s) 25. In embodiments that access the treatment location surgicallyor percutaneously via the femoral artery, for example, the first fluidport 27 can serve as the inlet to the pump 2, and the second ports 25can serve as the outlet(s) of the pump 2. The struts 19 can extenddistally beyond a distal end of the pump housing 35. In otherembodiments, however, the pump 2 can be inserted percutaneously throughthe left subclavian artery and advanced to the desired treatmentlocation in the descending aorta. In such arrangements, the pump 2 canbe positioned such that the distal end 22 of the system 1 is downstreamof the impeller 6, e.g., such that the distally-located first fluid port27 is downstream of the second fluid port(s) 25. In embodiments thataccess the treatment location through the left subclavian artery, thesecond fluid port(s) 25 can serve as the inlet(s) to the pump 2, and thefirst port 27 can serve as the outlet of the pump 2.

When the treatment procedure is complete, the pump 2 can be removed fromthe patient. For example, in some embodiments, the pump can be withdrawnproximally (and/or the sheath 28 can be advanced distally) such that adistal edge of the sheath 28 engages with a radially-outer facingsurface 43 of the struts 19. In some embodiments, the distal edge of thesheath 28 can engage with the knees 102 of the struts (see, e.g., FIGS.2A-3C). The distal edge of the sheath 28 can impart radially-inwardforces to the radially-outer facing surface 43 (e.g., at approximatelythe location of the knees 102) to cause the struts 19 to collapse and bedrawn inside the sheath 28. Relative motion opposite to that used fordeploying the pump 2 can be provided between the sheath 28 and the pump2 (e.g., between the sheath 28 and the impeller assembly 4 and pumphousing 35) to collapse the struts 19 into the sheath 28 in thecollapsed configuration. In some embodiments, the pump 2 can bewithdrawn from the sheath 28 with the sheath 28 in the patient's body,and the sheath 28 can be subsequently used for another procedure orremoved. In other embodiments, the sheath 28 and the pump 2 can beremoved together from the patient's body.

The foregoing description includes embodiments in which a proximal endof a drive shaft 51 is located in the drive unit 9. The proximal end ofthe drive shaft 51 and the motor 30 are disposed within the body in use.FIG. 1J shows another embodiment in which a motor 30A is disposedoutside the body in use. An elongate, flexible shaft 51′ is coupled at adistal end with the drive magnet 17. The shaft 51′ extends through anelongate body 20′ and is or can be coupled at a proximal end thereofwith a motor 30A. The motor 30A can be larger than the motor 30 since itneed not be disposed within the profile of the sheath 28. The elongatebody 20′ may have one or more lumens. The shaft 51′ may extend throughthe central lumen 55. One or more outer lumens 56 a may be provided toflow a fluid into the system to lubricate and/or cool the shaft 51′.Rotation of the proximal end of the shaft 51′ by the motor 30 a resultsin rotation of the entire length of the shaft 51′ through the elongatebody 20′ and also results in rotation of the drive magnet 17. Rotationof the drive magnet 17 causes rotation of one or more magnets in theimpeller 6 to create flow through the pump 2 by virtue of magneticattraction of these magnets across the distal drive unit cover. In otherembodiments, the shaft 51′ can be directly mechanically coupled to theimpeller 6 such that rotation does not depend on magnetic coupling. Oneor more shaft rotation supports 54A can be provided within a distalhousing 29A to support a distal portion of the shaft 51′. The elongatebody 20′ and/or the shaft 51′ can comprise a tether to control or to aidin control of the position of the pump, e.g., to counter thrust forcesof the impeller 6 to reduce or minimize movement of the pump 2 inoperation.

Additional details of the pump 2 and related components shown in FIGS.1A-1H may be found throughout International Patent Application No.PCT/US2020/062928, filed on Dec. 2, 2020, the entire contents of whichare incorporated by reference herein in their entirety and for allpurposes.

II. Struts

As explained herein, the support structure or localization system 100can comprise a plurality of struts 19. The struts 19 can have a firstfixed end 38 at the base portion 36 that is coupled to or formed withthe shroud 16, and a second free end 39 opposite the first end 38. Thestruts 19 can comprise projections extending from a housing (e.g., thepump housing 35) of a device, such as an intravascular device, extendingradially and distally outwardly to make constant or intermittent contactwith a vessel wall 37 (see FIGS. 4A-4B) of a vasculature system of apatient. As explained above, in other embodiments, the struts 19 mayextend proximally relative to the pump housing 35 and/or the motorhousing 29. As shown in, e.g., FIGS. 1A-1C, the struts 19 can extenddistal the first fluid port 27 and the impeller 6 along the longitudinalaxis L. In embodiments in which the vasculature is accessed through thefemoral artery, the struts 19 can extend distally and upstream of thefirst fluid port 27 and the impeller 6. In embodiments in which thevasculature is accessed through the subclavian artery, the struts 19 canextend downstream of the fluid port 27. The struts 19 can extend to andat least partially define a distal-most end of the blood flow assistsystem 1. In some embodiments, no portion of the blood flow assistsystem 1 is disposed distal the distal end of the struts 19. In someembodiments, the struts 19 may be made of a flexible shape set metal oralloy like nitinol. A support structure 100 including a plurality ofstruts 19 may be used to provide localization of an intravascular devicesuch as the pump 2. Using a plurality of struts 19 allows each of thestruts 19, by acting in opposition to each other, to transmit a radialforce to the region of the strut 19 in contact with the vessel wall 37.A plurality of struts 19 may also be effective in positioning anintravascular device (such as the pump 2) or part of an intravasculardevice relative to the vessel wall 37. For example, a plurality ofstruts 19 surrounding the first fluid port 27 (e.g., an inlet port insome embodiments) of the intravascular pump 2 effectively positions theinlet port 27 of the pump 2 at approximately the center of the bloodvessel 37. Struts 19 for localizing and positioning intravasculardevices may have a collapsed configuration for moving through the sheath28 (see FIG. 1H) for deployment or retrieval and an expandedconfiguration for providing localization and positioning.

FIG. 2A is an image showing a front perspective view of the localizationsystem 100A, according to one embodiment. FIG. 2B is a schematic sideview of the localization system 100A of FIG. 2A. FIG. 2C is a schematicplan view of a laser cut pattern for the localization system 100A. FIG.2D is a schematic side plan view of a strut 19A having a dome- orspherical-shaped contact pad 24A. Unless otherwise noted, the componentsof FIGS. 2A-2D may be the same as or generally similar to like-numberedcomponents of FIGS. 1A-1H, with some reference numbers appended by theletter “A.” As shown in, for example, FIGS. 2A-2D, each strut 19A cancomprise an elongate slender body that extends between the first end 38and the second end 39. Each strut 19A can comprise a material (e.g., ashape memory alloy) that is configured to store strain energy when atransverse compressive load is applied, e.g., compressively along theradial axis R. The stored strain energy can be employed to maintainlocalization and/or positioning relative to the vessel wall 37, asexplained herein. For example, the stored strain energy can be result inradially outward forces being applied against the vessel wall 37. Theradially outward forces can at least in part serve to localize,stabilize, and/or position the pump 2 relative to the vessel wall 37.

In some embodiments, a portion of the strut 19A that makes contact withthe vessel wall 37 may have a desired shape that aids localizationand/or positioning. In some embodiments, a portion of a strut 19A, suchas its second end 39, may comprise a contact element 104 configured tobe shaped as a generally flat contact pad 24A. In the illustratedembodiment, the contact pad 24A is shown as being generally circular ordomed. Other shaped ends may be suitable, such as an oval end or thelike. In some embodiments, shapes for the contact pad 24 that avoidsharp corners and/or edges may be preferred. When deployed, the contactpad 24A can be pressed against the wall 37 of the vessel with a radialforce transmitted by the strut 19A. As the pad 24A presses against thevessel wall 37, the vessel wall 37 may “pillow” up around the edges ofthe pad 24A or the pad may form a depression in which it sits. Theelongate struts can be configured to apply a load to the vessel wall 37(e.g., an aortic wall) when deployed to locally radially expand vesselwall tissue against which the contact pad 24A is apposed. For example,the contact pad 24 can be resiliently deflectable toward and away fromthe longitudinal axis L of the pump housing 35. The contact pad 24 canhave a free state being spaced away from the longitudinal axis L of thepump housing 35 by a distance greater than a half-width of a bloodvessel 37 into which the pump housing 35 is to be deployed.

The contact pad 24 can apply sufficient force to a wall of the bloodvessel 37 to depress or pillow a portion of the contact pad 24 into thewall. The contact pad 24 can be configured to engage without hooking thewall of the blood vessel 37 when applied. In some arrangements, thestruts 19A can flex with vessel wall movement (e.g., with vessel wallexpansion and contraction) such that the struts 19A can maintain contactwith the vessel 37 even when the vessel 37 expands or contracts. Thispillowing may enhance the ability of the strut 19A and pad 24A tolocalize the intravascular device (e.g., pump 2) by resisting slidingmotion of the pad 24A. The amount that the pad 24A presses into thevessel wall 37 (and therefore the amount of pillowing) may be controlledby adjusting the radial force the strut 19A transmits to the contact pad24A. The pad 24A may have holes or irregular edges to enhance thepillowing effect.

As shown in FIGS. 2E-2G, struts 19A′ may include contact pads 24B having“slide runner” edges 66 that flare or bevel away from the vessel wall 37so that sharp edges are not pressed into the vessel wall 37. As shown inFIGS. 2E-2G, the contact pads 24B can include a contact surface 67 thatengages and depresses into the vessel wall 37, such that a surroundingportion of the wall 37 extends radially inward relative to at least aportion (e.g., the contact surface 67) of the contact pad 24B thatengages the wall 37. The profile of the pad 24B in FIGS. 2E-2G includingthe edge 66, the contact surface 67, and the elongate member of thestrut 19A can define a convex profile or shape. In the illustratedarrangement, the contact surface 67 can comprise a generally planar orflat shape, and the edge 66 can extend at an obtuse angle relative tothe contact surface 67. In some embodiments, the contact surface 67 cancomprise a curved surface, such as a convex spherical or domed surface.Such designs reduce or minimize the potential for traumatic injury tothe vessel wall 37, are non-endothelializing, and may aid removalwithout damaging the vessel. With sufficient radial force and pillowing,such designs may provide stable localization of the strut contact pad24A.

As shown in FIGS. 2A-2B, the struts 19A can comprise knees 102 that canserve to keep the strut 19A away from the inner wall of the sheath 28when the plurality of struts 19A is collapsed within the sheath 28, asshown above in FIG. 1H. The sheath 28 can comprise an inflection inwhich the curvature of the radially-outward facing surface of the strut19A changes. As shown in FIG. 2B, for example, the struts 19A cancomprise a plurality of segments 103 a-103 d that are integrally formedand connected with one another. A first segment 103 a can extend fromthe base portion 36A distally and radially outwardly by an angle Arelative to the longitudinal axis L. A second segment 103 b can extenddistally and radially inwardly from the distal end of the first segment103 a by an angle B relative to the longitudinal axis L. A third segment103 c can extend distally and radially outwardly from the distal end ofthe second segment 103 b by an angle C relative to the longitudinal axisL. A fourth segment 103 d can extend distally and radially inwardly fromthe distal end of the third segment 103 c by an angle D relative to thelongitudinal axis L.

Thus, as shown in FIG. 2B, the struts 19A can have multiple changes incurvature and/or angles along the lengths of the struts 19A. In variousembodiments, the angle A can be in a range of 30° to 70°, in a range of40° to 60°, or in a range of 45° to 55° relative to the longitudinalaxis L. The angle B can be in a range of 10° to 30°, in a range of 15°to 25°, or in a range of 18° to 24° relative to the longitudinal axis L.The angle C can be in a range of 20° to 60°, in a range of 30° to 50°,or in a range of 35° to 45° relative to the longitudinal axis L. Theangle D can be in a range of 20° to 45°, or in a range of 25° to 35°relative to the longitudinal axis L. The base portion 36A can have afirst height H1 in a range of 0.1″ to 0.3″. In the expandedconfiguration, the radial separation along the radial axis R between theends of the struts 19A can have a second height H2 in a range of 1″ to2″, or in a range of 1.2″ to 1.6″.

Beneficially, the use of multiple angles and curvatures for the struts19A can enable the struts 19A to provide sufficient localization andsupport for the pump 2. Additionally or alternatively, the use ofmultiple angles and/or curvatures for the struts can adequately spaceparts of the struts, for example the free ends of the struts 19A, fromthe inner wall of the sheath 28. The spacing of the pads 24A from theinside wall of the sheath 28 can reduce friction and/or damage to thestruts 19A and/or sheath 28 when the pump 2 is moved within and/or intoand out of the sheath 28. Further, as explained above, the flat contactpads 24A can beneficially provide an atraumatic interface between thestruts 19A and the vessel wall 37 that provides sufficient localizationand/or positioning. The struts 19A can be manufactured by laser cuttinga shape memory alloy as shown in, e.g., the laser cut pattern in a sheetof material of FIG. 2C. The shape memory alloy (e.g., nitinol) can becut with a laser or other device and shaped to form the struts 19A. Thepatterned material can be folded and/or rolled into a closed generallycylindrical profile. In other embodiments, the pattern can be cut froman already-formed tube.

In some embodiments, such as that shown in FIG. 2D, the contact pad 24Aor distal portion of the strut 19A may include a spherical ordomed-shaped profile 42 that serves as the contact surface 67. As anonlimiting example, the spherical profile 42 may be formed as a ball ofplastic or other material formed on the portion of the strut 19A tocontact the vessel wall 37. As shown in FIGS. 2B-2D, for example, thespherical profile 42 can be disposed on a radially-outer surface 43 ofthe strut 19A that is configured to face and engage with the vessel wall37. A radially-inner wall 44 can be disposed radially opposite theradially-outer surface 43. In FIG. 2C, the struts 19A can becircumferentially spaced apart such that there is a respective gap 45between adjacent side surfaces of adjacent struts 19A of the pluralityof struts 19A. A spherical contact feature 24A can be beneficiallyatraumatic, and may provide good pillowing and resistance totranslation. As shown the contact pad 24A can comprise a generallycircular (or elliptical) pad in a profile view that has a diametergreater than a width of an immediately adjacent expanse of thecorresponding elongate strut 19A. The contact pad 24A can comprise anelongate member and an enlarged blood vessel wall contact surface (e.g.,surface 67 in FIGS. 2D-2G) disposed at the end of the elongate member.In various embodiments, the contact pad 24A can comprise a convexcross-sectional profile along the radially-outer surface 43 of the strut19A that faces the vessel wall 37. For example, the contact pads 24A cancomprise a convex profile in a cross-sectional plane disposed transverseto the longitudinal axis L of the pump housing 35. In some embodiments,the contact pads 24A can comprise smooth surfaces free of sharp edges orhooks. In some embodiments, each of the contact pads 24A can compriseone or more scalloped edges to allow tissue of the vessel wall 37 to bereceived therein.

In some embodiments, the localization system 100A may have the goal ofresisting, but not eliminating, the translation or rotation of a device(such as the pump 2) relative to the vessel wall 37. As a nonlimitingexample, some strut 19A and/or contact pad 24A designs may allow somesmall degree of rotation of the device within the vessel, even whendeployed. However, such designs may also leverage other featuresdiscussed herein to further increase resistance to rotation duringoperation of the device, such as increase resistance resulting frompropulsion.

Alternatively, some embodiments of the contact pad may by designed toincrease resistance to translation and/or rotation relative to thevessel wall 37. FIG. 3A is an image of a front perspective of alocalization system 100B according to another embodiment. FIG. 3B is animage of a side view of the localization system 100B of FIG. 3A. FIG. 3Cis a schematic side view of the localization system 100B of FIGS. 3A-3B.FIG. 3D is a schematic enlarged view of the second end 39 of the strut19B of FIGS. 3A-3C. FIGS. 3E and 3F are schematic plan views of thelocalization system 100B in a laser cut pattern prior to assembly.Unless otherwise noted, the components of FIGS. 3A-3F may be the same asor generally similar to like-numbered components of FIGS. 1A-2C, withsome reference numbers appended by the letter “B.” In some embodiments,the contact element 104 (e.g., the portion of the strut 19B in contactwith the wall 37 of the vessel) may comprise a hook 105 designed topenetrate the vessel wall 37 to provide a stable anchor point that has ahigh level or resistance to translation and/or rotation. Designs withedges or hooks 105 in constant contact with the vessel wall aretypically intended to provide stable localization and/or positioning sothere is little or no motion of the hook 105 or edge relative to theinitial contact region of the vessel wall 37 when deployed.

As shown in FIG. 3C, the struts 19B can comprise a plurality of segments106 a-106 d that are integrally formed and connected with one another. Afirst segment 106 a can extend from the base portion 36B distally andradially outwardly by an angle E relative to the longitudinal axis L. Asecond segment 106 b can extend distally and radially inwardly from thedistal end of the first segment 106 a so as to at least partially definean inflection point and/or knee 102 as explained above. A third segment106 c can extend distally and radially outwardly from the distal end ofthe second segment 106 b by an angle F relative to the longitudinal axisL. A fourth segment 106 d can extend back proximally from the distal endof the third segment 106 c by an angle G relative to the third segment106 c. The third and fourth segments 106 c, 106 d can serve as the hook105 and can secure the pump 2 to the vessel wall 37. As shown in FIG.3G, which is a plan view of the fourth segment 106 d, the fourth segment106 d of the strut 19B can include a split 106 e having tines that cansecure to a vessel wall, in some embodiments. As shown, in someembodiments, a tine width t_(w) can be in a range of, e.g., 0.01″ to0.1″, or in a range of 0.01″ to 0.05″.

As shown in FIG. 3C, the struts 19B can have multiple changes incurvature and/or angles along the lengths of the struts 19B. In variousembodiments, the angle E can be in a range of 30° to 70°, in a range of40° to 60°, or in a range of 45° to 55° relative to the longitudinalaxis L. The angle F can be in a range of 20° to 60°, in a range of 30°to 50°, or in a range of 35° to 45° relative to the longitudinal axis L.The angle G can be in a range of 40° to 80°, in a range of 50° to 70°,or in a range of 55° to 65° relative to the segment 106 c, angledproximally as shown. The base portion 36B can have a first height H1 ina range of 0.1″ to 0.3″. In the expanded configuration, the radialseparation along the radial axis R between the ends of the struts 19Bcan have a second height H2 in a range of 1″ to 2″, or in a range of 1″to 1.4″. Further, as shown in FIG. 3C, the knee 102 can have a bumpheight h_(b) that indicates the amount of the bulge or bump defined bythe knee 102. The bump height h_(b) can be measured between anoutwardly-facing crest of the knee 102 and a projection of the thirdsegment 106 c. In various embodiments, the bump height h_(b) can be in arange of 0.03″ to 0.09″, or in a range of 0.05″ to 0.07″ (e.g., about0.054″ in one embodiment). In addition, the fourth segment 106 d canserve as a tine of the hook 105 and can have a tine length l_(t)extending proximally from the third segment 106 c. The tine length l_(t)can be in a range of 0.03″ to 0.09″, or in a range of 0.05″ to 0.07″(e.g., about 0.058″ in one embodiment).

FIGS. 3E-3F show laser patterns for the system 100B of FIGS. 3A-3D. Asshown in FIGS. 3E-3F, in some embodiments, the struts 19B can be taperedacross their width from proximal to distal along their length, i.e.,from right to left in FIGS. 3E-3F. Laser cuts can be made non-normal tothe longitudinal axis, which can create a helical or spiral pattern invarious arrangements.

FIG. 5A is a schematic perspective view of a localization system 100Caccording to another embodiment. FIG. 5B is a schematic plan view of alaser cut design for the system 100C of FIG. 5A. Unless otherwise noted,the components of FIGS. 5A-5B may be the same as or generally similar tolike-numbered components of FIGS. 1A-4E, with some reference numbersappended by the letter “C.” In some embodiments, as shown in FIGS.5A-5B, the plurality of struts 19C may differ in length. For example, asshown in FIGS. 5A-5B, the system 100C an include struts 19C arranged ina jester hat design. As shown, adjacent struts 19C may have differentlengths. In some embodiments, every other strut may be designed to haveapproximately the same length. For example, as shown in FIGS. 5A-5B,first struts 19C′ of the plurality of struts 19C may have a firstlength, and second struts 19C″ of the plurality of struts 19C may have asecond length 19C″ shorter than the first length. The second struts 19C″may each be disposed circumferentially between the first struts 19C′.Although not illustrated in FIGS. 5A-5B, the struts 19C can includecontact pads 24 at distal end portions thereof. In other embodiments,the struts 19C can include hooks 105 at distal end portions thereof.

Without being limited by theory, the different lengths may enable thesystem 100C to be supported against the vessel 37 at a plurality oflongitudinal locations along the length of the vessel 37, which canimprove localization and positioning. For example, in the expandedconfiguration of the struts 19C′, 19C″, the first struts 19C′ can engagewith the vessel wall 37 at a location distal the location at which thesecond struts 19C″ engages with the vessel wall 37, such that the firstand second struts 19C′, 19C″ engage with the vessel wall 37 at offsetlongitudinal positions. Engagement at offset longitudinal positions ofthe vessel wall 37 can beneficially improve stabilization of the pump 2along multiple planes, and can also provide a resisting moment withmultiple planes of contact. Moreover, the differing lengths of thestruts 19C′, 19C″ can improve collapsibility of the struts by allowingthe sheath 28 to separately engage the struts 19C′ and 19C″. Forexample, due to the differing lengths (and/or curvature) of the struts19C′, 19C″, the sheath 28 may first engage a first set of struts (e.g.,struts 19C″ in some embodiments) to cause the first set of struts tobegin collapsing. During or after collapse of the first set of struts,the sheath 28 may subsequently engage a second set of struts (e.g.,struts 19C′ in some embodiments) to cause the second set of struts tocollapse. Dividing the collapse of the struts 19C′, 19C″ into two ormore stages can beneficially reduce the amount of force used to collapsethe respective struts 19C′, 19C″.

It should be appreciated that any of the support structures disclosedherein can comprise struts having different lengths. For example, insome embodiments, the plurality of struts (e.g., struts 19 or 19A)includes a first plurality of struts and a second plurality of struts.When the plurality of struts are in an expanded configuration, firstcontact elements (e.g., contact pads 24 or hooks 105) of the firstplurality of struts can be configured to engage with the blood vesselwall at a first longitudinal position and second contact elements (e.g.,contact pads 24 or hooks 105) of the second plurality of struts can beconfigured to engage with the blood vessel wall at a second longitudinalposition that is spaced from the first longitudinal position. In someembodiments, the struts in the first plurality can have a differentlength from the struts in the second plurality. Additionally oralternatively, the struts in the first plurality can have a differentradius of curvature (or departure angle) from the struts in the secondplurality.

FIG. 6 is a schematic side view of a plurality of struts 19D accordingto various embodiments. In some embodiments, as shown in FIG. 6, a firstset of struts 19D′ may have an elongate portion with a first radius ofcurvature, and a second set of struts 19D″ may have an elongate portionwith a second radius of curvature different than (e.g., less than) thefirst. In the arrangement of FIG. 6, the first struts 19D′ have asteeper takeoff angle relative to the longitudinal axis L as comparedwith the second struts 19D″. An angle between a longitudinal axis of thepump 2 and of a portion of the second struts 19D″ adjacent to a baseportion to which the struts are connected can be greater than acorresponding angle for the first struts 19D′, as shown in FIG. 6. Thesteeper takeoff angle of the first struts 19D′ may cause the sheath 28to engage with and initiate collapse of the first struts 19D′ beforeengagement with the second struts 19D″. As explained above, staging,staggering or sequencing the collapse of the struts 19D′, 19D″ canbeneficially reduce the force used to collapse the struts so as toimprove operation of the pump 2. Staging, staggering, or sequencing thecollapse of the struts can modulate the force profile over the length ofmotion of the sheath 28 over the struts 19 as felt from initial movementprior to collapsing, to the initial collapsing adjacent to the base 36,to final and full collapsing of the struts 19 by advancing the sheathadjacent to or beyond the distal ends of the struts. Staging,staggering, or sequencing can reduce the maximum force required over thelength of motion of the sheath 28 over the struts 19. Moreover, thedifferent curvature of the struts 19D′, 19D″ may also allow the distalends of the struts 19D′, 19D″ to engage the vessel wall 37 at offsetlongitudinal positions, which, as explained above, can improvestabilization of the pump 2 due to, e.g., multiple planes or rings ofcontact with the vessel wall 37.

FIG. 6 thus illustrates embodiments where the struts 19D′, 19D″ may haveapproximately the same length along the longitudinal direction fromproximal to distal ends in the retracted state but which may expand tocontact a vessel wall at offset longitudinal positions, e.g., as may bedefined by two spaced apart planes disposed transverse to, e.g.,perpendicular to the longitudinal axis of the pump 2. The struts 19D′,19D″, individually or in groups defining contact planes, can at leastintermittently contact the vessel wall over a range of positions alongthe vessel wall that is two times, three times, four times, five times,six times, up to ten time, or up to one hundred times greater than thecontact length of a contact pad or other vessel wall contact surface ofthe struts. It will be appreciated that dispersed contact areas of thesesorts can also be provided by struts that have different lengths in theretracted state, as in FIGS. 5A-5B. In some embodiments, the contactelement 104 at the second free end 39 of a strut 19D may be curled orcoiled so that curled portion will contact the vessel wall 37. As anonlimiting example, the second free end 39 of the strut 39D may becurled or coiled (e.g., at an angle in a range of approximately 270° to)360°.

The contact area of the contact element 104 of a strut 19-19D may bedesigned so that endothelialization over longer durations does notimpede or prevent removal of the device or increase the potential fortrauma to the vessel wall 37 when the intravascular device (e.g., pump2) is removed. In general, single-ended contact geometries can be pulledout more easily from under any endothelialization. In contrast,non-single ended contact geometries may increase the potential fortrauma to the vessel wall 37 when the device is removed. In someembodiments with hooks 105, the strut 19B can be shaped so the action ofadvancing the sheath 28 to collapse the plurality of struts 19B willmove the struts 19B in such a way as to pull the hooks 105 from thevessel wall 37 like a dart from a dartboard or in the opposite directionfrom which it was inserted. In some embodiments with contact pads 24,24A, the pads 24, 24A may be tapered so they can be pulled out fromunder endothelialized tissue by translating the intravascular device(e.g., pump 2). Raising the edges of the contact pad 24, 24A (e.g., a“sled”-type design) may also discourage restrictive endothelialization.

The amount of radial force that presses the contact area at the secondfree end 39 of a strut 19-19D against the blood vessel wall 37 can bealtered by varying the number of struts 19-19D, material of the struts19-19D, and/or the geometry of the struts 19-19D and contact pads24-24A. Important geometric factors may include, but are not limited to,the length of the strut 19-19D, cross-section of the strut 19-19D,attachment angle of the strut 19-19D to the pump housing 35, andcurvature of the strut 19-19D. In general, a strut 19-19D will have aspring function, such that the more the strut 19-19D is compressed bythe vessel wall 37, the higher the radial force of the strut 19-19D onthe vessel wall 37. The design and shape forming of the strut may beselected to reduce this dependence so that the radial force provided bythe strut 19-19D is relatively independent of the radius to which thestrut is compressed. Equalization of such spring forces among aplurality of struts 19-19D can provide a centering positioning effect.

In some embodiments, a strut 19-19D may be designed for intermittentcontact and have zero radial force unless it is in contact with thevessel wall 37. As a nonlimiting example, the plurality of struts 19-19Dmay have different lengths and/or geometries (e.g., FIGS. 5A-5B). Thedifferent lengths and/or geometries may arrange the struts 19C so thatnot all struts 19C touch the vessel wall 37 at the same time in someembodiments as shown in FIGS. 5A-5B. Further, is some example the struts19-19D may be utilized with devices that exert forces on the struts19-19D during operation (e.g., a gyroscopic effect), which may result inchanges in forces exerted on the struts 19-19D. Because of thespring-like nature of the struts 19-19D, collapse or release in suchsituations can be facilitated. Note that each strut 19-19D in aplurality of struts may have a different geometry or contact regiondesign.

In some embodiments, the struts 19-19D can have knees 102 as explainedabove. A knee 102 in a strut may function to keep part of the strut19A-19D away from the inner wall of the sheath 28 when the plurality ofstruts 19A-19D are collapsed within the sheath 28. For example, the knee102 may function to keep a hook 105 away from the inner wall of thesheath 28 so that the hook 105 does not contact the sheath 28 and createparticulates through abrasion, cutting, or gouging. The knee 102 cancomprise an inflection zone disposed between the first end 38 and thesecond end 39, the second end 39 resiliently deflectable toward and awayfrom the longitudinal axis L of the pump housing 35. A free state of thestrut can space the second end 39 thereof away from the longitudinalaxis L of the pump housing 35. The second end 39 of the strut can beconfigured to engage the blood vessel wall 37 (e.g., to at leastintermittently contact the vessel wall 37). The inflection zone cancomprise an S-connection between a first span of the strut and a secondspan of the strut. The first span and the second span can be disposedalong parallel trajectories.

Minimizing the diameter of the sheath 28 used to implant or retrieve anintravascular device (such as the pump 2) can be important. An advantageof the embodiments disclosed herein is that the plurality of struts19-19D can be collapsed to a diameter equal to or smaller than thediameter of the pump 2 itself so that a large sheath is not required dueto the presence of the plurality of struts 19-19D.

In some embodiments, a plurality of struts 19-19D may be designed tocontact the vessel wall 37 in multiple transverse planes (for example,at multiple longitudinal positions) along the central axis of thevessel. In some embodiments, a plurality of struts 19-19D may beattached to the pump 2 in one transverse plane, but the struts 19-19Dcan have different geometries and can contact the vessel wall 37 inmultiple transverse planes along the central axis of the vessel. In someembodiments the plurality of struts 19-19D may be attached to the pump 2in more than one transverse plane along the central or longitudinal axisL of the pump 2. As a nonlimiting example, there may be a set of struts19-19D at each end of the pump 2 (e.g., at proximal and distal ends ofthe pump 2).

In some embodiments, a plurality of struts 19-19D may be directlyintegrated into the pump 2 such that the shroud 16 and struts 19-19D aremonolithically formed in a single piece. In other embodiments, theplurality of struts 19-19D may be coupled or connected to the pump 2instead and may comprise one or more separate piece(s). As a nonlimitingexample, the struts 19-19D may be attached a ring that is attached tothe pump 2.

Tether

In some embodiments, one or more tethers may be a component of thelocalization and positioning system 100-100C. Devices, such as the pump2, that utilize a cable or lead for power or infusion can use that cableor lead as a tether. For example, as shown herein, the power lead 20 canserves as the tether in the illustrated embodiments. The tether (e.g.,power lead 20) can have an anchor point outside the blood vessel and/orthe patient, and can limit translation of the intravascular device (e.g.away from that anchor point). As explained herein, for example, theconnector 23 at the proximal end 21 of the system 1 can connect to aconsole (which can serve as the anchor point in some embodiments)outside of the patient's body. In some embodiments, the arteriotomy andpath through the skin of the patient can serve as the anchor point forthe tether. Sutures may be used to anchor the tether (e.g., power lead20) adjacent to the proximal end 21 in some procedures.

Propulsion

One nonlimiting example of intravascular devices that may be used withthe disclosed embodiments is the blood pump 2A, as shown in, e.g., FIGS.4A-4E. As shown in FIG. 4A, and as explained above, the sheath 28 can beinserted percutaneously to a treatment location in a blood vessel, suchas the descending aorta. In some embodiments, as shown in FIG. 4B, afterplacement of the sheath 28, the pump 2A can be pushed distally withinthe sheath 28 by way of a stiffening member or guidewire (not shown)that can be disposed within the central lumen 55. In other embodiments,the pump 2A can be pre-loaded in the sheath 28, and the sheath 28 andpump 2A can be advanced together to the treatment location. As shown inFIGS. 4C-4D, relative motion can be provided between the sheath 28 andthe pump 2A to urge the pump 2A out of the sheath 28. The supportstructure including the struts 19-19D can self-expand and contact theinner wall of the vessel 37. The struts used in the support structure ofthe pump 2A shown in FIGS. 4A-4E can include any of the struts 19-19Ddescribed herein. For example, in some embodiments, such as that shownin FIG. 4C, a mesh 47 can extend or span between adjacent struts at alocation near the distal end of the shroud 16. The mesh 47 can extendpartially along length(s) of the struts, e.g., within a range of 10% to70% of a length of the strut(s). The struts 19A of FIG. 4D are shownwith the contact pads 24. The struts of FIG. 4E are shown with the hooks105.

Once the struts are deployed, the impeller 6 can be activated to pumpblood. Some blood pumps 2A discharge blood in jets 34 or exertsignificant forces during operation. These pumps 2A may generate areaction (or propulsive) force 33 on the pump 2A in the oppositedirection of the pump discharge, e.g. when pumping down a propulsiveforce 33 may result upwardly as shown in FIG. 4D. Some embodiments maybe designed to take advantage of this propulsive force 33 as a componentof the localization system 100-100C. As a nonlimiting example, thestruts 19-19D may provide a geometry that causes an increase in thespring-like forces as a result of the propulsive force 33, e.g., thepropulsive force 33 may further compress the struts 19-19D and increasethe spring force. In various embodiments, a longitudinal component ofthe thrust force 33 along the longitudinal axis L can be opposed bytension in the tether (e.g., the power lead 20). A transverse componentof the thrust force 33 directed transverse to the longitudinal axis L(e.g., along the radial axis R) can be opposed by strain energy storedin at least one of the elongate struts 19-19D upon deflection of thestrut(s) 19-19D. As explained herein, when the procedure is complete,the clinician can provide further relative motion between the sheath 28and the pump 2A to collapse the struts 19-19D into the sheath 28 (seeFIG. 1H).

Beneficially, in various embodiments disclosed herein, the power lead 20can serve as a tether that is sufficiently strong so as to oppose loadsapplied in opposite directions at opposite ends thereof. In some pumps,the thrust from the pump 2 may be too strong such that, if the proximalend of the tether is not sufficiently anchored and/or if the power lead20 is not sufficiently strong, the pump 2 can move through the bloodvessel. In such a situation, the pump 2 may stretch the tether, and/orthe tether may not be sufficiently anchored. Beneficially, theembodiments disclosed herein can utilize the elongate hollow member andconductor wires which can be sufficiently strong such that, whenanchored outside the blood vessel, a longitudinal component of thethrust force generated by the impeller directed along the longitudinalaxis of the pump can be adequately opposed by the tether. Thus, invarious embodiments, the tether (e.g., power lead 20) can be configuredto maintain a position of the pump 2 within the blood vessel withoutrequiring contact between the pump 2 and a blood vessel wall 37 of theblood vessel.

In some embodiments, the struts of the support structure need notcontact the wall 37 during operation of the blood pump 2, and the tethercan serve to adequately position the pump 2. In some procedures, thestrut(s) may at least intermittently contact the blood vessel wall 37(e.g., the struts may only intermittently contact the wall 37). In sucharrangements, the strut(s) may intermittently come into contact with thewall 37 and move away from the vessel wall 37 throughout the procedure.Accordingly, the embodiments disclosed herein need not require constantcontact between the support structure of the pump and the vessel wall37. Indeed, in such embodiments, the struts may comprise short and/orstubby struts that may serve as bumpers that atraumatically, e.g.,resiliently, engage with the vessel wall 37 intermittently as the pump 2moves towards the wall 37, and pushes the pump 2 back towards a centrallocation of the vessel. In some embodiments, the struts may be omittedsuch that the tether and thrust force establish the position of the pumpin operation. In other embodiments, however, the struts may be shaped orconfigured to maintain substantially constant contact with the vesselwall 37 when in the deployed configuration during use of the pump 2. Instill other embodiments, the pump 2 may not include struts, such thatthe tether may serve the positioning and/or localization functionwithout struts.

Example Designs

The various design features discussed above may be mixed and combined inany fashion desired. Nonlimiting examples described herein belowillustrate one possible embodiment that combines the design elementsdescribed above and are not an indication of the bounds of potentialcombinations.

The systems and methods discussed herein are used to providelocalization and positioning of a device, such as an intravascular pump2, 2A. A plurality of struts 19-19D with contact elements 104 projectout from a ring attached to the inlet end of the pump 2. The embodimentsof FIGS. 1A-3G show four struts 19-19B, but any number of struts may beused. For example, as shown in FIGS. 5A-5B, in some embodiments morethan four struts (e.g., six struts 19C) can be used. The contact pads24, 24A are shown as circular, but any shaped contact pads 24, 24A maybe used. The strut geometry is designed to provide radial force within aset range at the strut contact pads 24, 24A for vessels within a certaindiameter range. The struts 19-19D can also be designed to reduce orminimize the force required for the sheath 28 to collapse the struts19-19D.

The circular contact pads 24, 24A can be designed to slide on the innerartery wall 37 rather than cause any trauma. With this tuning of theradial force, the plurality of expanded struts 19-19D providesconsistent positioning of the inlet port 27-27B of the pump 2, 2 a inthe center of the vessel lumen and resists, but does not strictlyprevent, translation and rotation of the pump 2, 2 a. This featureallows safe translation of the pump 2, 2 a whether intentional (to movethe pump 2, 2A to a preferred location) or unintentional (e.g., if thepower lead is yanked).

Providing limited localization is sufficient because in some embodimentsthe propulsive force 33 of the pump 2, 2A tends to move it in a superiordirection, and/or this movement may be limited by the tether effect ofthe pump's power lead 20. One advantage of this embodiment is providingstable long-term localization, while allowing instantaneous movement ofthe pump 2, 2A with minimal or reduced risk of trauma to the vessel wall37. This embodiment, for example, is compatible with a greaterfreedom-of-motion for the patient who is free to sit up, bend at thewaist, and/or make other similar motions.

In some embodiments, the strut geometry may be altered so that thestruts 19-19D only make intermittent contact with the vessel wall 37. Insuch an embodiment, the propulsive force 33 acting against the tether(e.g., power lead 20) provides localization and the struts 19-19Dmaintain positioning of the port 27-27B of the pump 2, 2A in the centerof the lumen of the vessel.

Advantages

The systems and methods discussed herein, including without limitationthe embodiment described in detail and illustrated in the drawings, hasa number of advantages. Many of these advantages are described above.The following are only additional non-limiting examples of advantages,some of which arise from the combination of various design elements.

-   -   a. Struts 19-19D (including struts 19C′, 19C″, 19D′, 19D″)        designed to not increase the diameter of the pump 2 when the        struts 19-19D are in the collapsed configuration.    -   b. Struts 19-19D (including struts 19C′, 19C″, 19D′, 19D″) with        knees 102 and hooks 105, such that the knees 102 prevent the        hooks 105 from contacting the inner surface of the sheath 28        during implantation or retrieval of the pump 2.    -   c. Atraumatic contact pads 24, 24A designed to resist, but not        eliminate translation or rotation of the intravascular device        (e.g., pump 2, 2A) that        -   i. Work in conjunction with a tether (e.g., power lead 20)            and propulsive force 33; and/or        -   ii. Become more resistant to translation over time due to            desired endothelialization.    -   d. Intermittent contact positioning (centering) with struts        19-19D (including struts 19C′, 19C″, 19D′, 19D″) with long-term        localization effected by the propulsive force 33 working against        a tether (e.g., power lead 20).

Embodiments described herein are included to demonstrate particularaspects of the present disclosure. It should be appreciated by those ofordinary skill in the art that the embodiments described herein merelyrepresent exemplary embodiments (e.g., non-limiting examples) of thedisclosure. Those of ordinary skill in the art should, in light of thepresent disclosure, appreciate that many changes can be made in thespecific embodiments described, including various combinations of thedifferent elements, components, steps, features, or the like of theembodiments described, and still obtain a like or similar result withoutdeparting from the spirit and scope of the present disclosure. From theforegoing description, one of ordinary skill in the art can easilyascertain the essential characteristics of this disclosure, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications to adapt the disclosure to various usages andconditions. The embodiments described hereinabove are meant to beillustrative only and should not be taken as limiting of the scope ofthe disclosure.

Prior work is detailed in U.S. Pat. No. 8,012,079 and U.S. Pat. Pub. No.2017/0087288, which are both fully incorporated by reference herein.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, and/or steps are inany way required for one or more embodiments.

The terms “comprising,” “including,” “having,” and the like aresynonymous and are used inclusively, in an open-ended fashion, and donot exclude additional elements, features, acts, operations, and soforth. Also, the term “or” is used in its inclusive sense (and not inits exclusive sense) so that when used, for example, to connect a listof elements, the term “or” means one, some, or all of the elements inthe list. In addition, the articles “a,” “an,” and “the” as used in thisapplication and the appended claims are to be construed to mean “one ormore” or “at least one” unless specified otherwise.

The ranges disclosed herein also encompass any and all overlap,sub-ranges, and combinations thereof. Language such as “up to,” “atleast,” “greater than,” “less than,” “between,” and the like includesthe number recited. Numbers preceded by a term such as “about” or“approximately” include the recited numbers and should be interpretedbased on the circumstances (e.g., as accurate as reasonably possibleunder the circumstances, for example ±5%, ±10%, ±15%, etc.). Forexample, “about 1” includes “1.” Phrases preceded by a term such as“substantially,” “generally,” and the like include the recited phraseand should be interpreted based on the circumstances (e.g., as much asreasonably possible under the circumstances). For example,“substantially spherical” includes “spherical.” Unless stated otherwise,all measurements are at standard conditions including temperature andpressure.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: A, B, or C” is intended to cover: A, B, C,A and B, A and C, B and C, and A, B, and C. Conjunctive language such asthe phrase “at least one of X, Y and Z,” unless specifically statedotherwise, is otherwise understood with the context as used in generalto convey that an item, term, etc. may be at least one of X, Y or Z.Thus, such conjunctive language is not generally intended to imply thatcertain embodiments require at least one of X, at least one of Y and atleast one of Z to each be present.

Although certain embodiments and examples have been described herein, itshould be emphasized that many variations and modifications may be madeto the humeral head assembly shown and described in the presentdisclosure, the elements of which are to be understood as beingdifferently combined and/or modified to form still further embodimentsor acceptable examples. All such modifications and variations areintended to be included herein within the scope of this disclosure. Awide variety of designs and approaches are possible. No feature,structure, or step disclosed herein is essential or indispensable.

Some embodiments have been described in connection with the accompanyingdrawings. However, it should be understood that the figures are notdrawn to scale. Distances, angles, etc. are merely illustrative and donot necessarily bear an exact relationship to actual dimensions andlayout of the devices illustrated. Components can be added, removed,and/or rearranged. Further, the disclosure herein of any particularfeature, aspect, method, property, characteristic, quality, attribute,element, or the like in connection with various embodiments can be usedin all other embodiments set forth herein. Additionally, it will berecognized that any methods described herein may be practiced using anydevice suitable for performing the recited steps.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures are described herein. It is to be understood that notnecessarily all such advantages may be achieved in accordance with anyparticular embodiment. Thus, for example, those skilled in the art willrecognize that the disclosure may be embodied or carried out in a mannerthat achieves one advantage or a group of advantages as taught hereinwithout necessarily achieving other advantages as may be taught orsuggested herein.

Moreover, while illustrative embodiments have been described herein, itwill be understood by those skilled in the art that the scope of theinventions extends beyond the specifically disclosed embodiments to anyand all embodiments having equivalent elements, modifications,omissions, combinations or sub-combinations of the specific features andaspects of the embodiments (e.g., of aspects across variousembodiments), adaptations and/or alterations, and uses of the inventionsas would be appreciated by those in the art based on the presentdisclosure. The limitations in the claims are to be interpreted fairlybased on the language employed in the claims and not limited to theexamples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive. Further, the actions of the disclosed processes andmethods may be modified in any manner, including by reordering actionsand/or inserting additional actions and/or deleting actions. It isintended, therefore, that the specification and examples be consideredas illustrative only, with a true scope and spirit being indicated bythe claims and their full scope of equivalents.

What is claimed is:
 1. A blood flow assist system comprising: animpeller disposed in a pump housing of a pump, the pump comprising alongitudinal axis, the impeller generating a thrust force when operatingin a blood vessel to pump blood; and a tether extending away from thepump housing, the tether configured to oppose loads applied in oppositedirections at opposite ends thereof, wherein a longitudinal component ofthe thrust force generated by the impeller directed along thelongitudinal axis of the pump is opposed by the tether, the tetherconfigured to maintain a position of the pump within the blood vesselwithout requiring contact between the pump and a blood vessel wall ofthe blood vessel.
 2. The blood flow assist system of claim 1, furthercomprising a support structure coupled to or formed with the pumphousing, the support structure configured to at least intermittentlycontact the blood vessel wall to maintain spacing of the pump housingfrom the blood vessel wall in which the pump housing is disposed.
 3. Theblood flow assist system of claim 2, wherein the support structurecomprises a plurality of elongate struts having a first end coupled withthe pump housing and a second end opposite the first end, each elongatestrut of the plurality of struts having a slender body and extendingbetween the first end and the second end.
 4. The blood flow assistsystem of claim 3, further comprising convex contact pads disposed atrespective distal portions of the plurality of struts, the convexcontact pads configured to at least intermittently contact the bloodvessel wall to maintain spacing of the pump housing from a blood vesselwall in which the pump housing is disposed.
 5. The blood flow assistsystem of claim 4, wherein the plurality of struts includes a firstplurality of struts and a second plurality of struts, wherein, when theplurality of struts are in an expanded configuration, first contact padsof the first plurality of struts are configured to engage with the bloodvessel wall at a first longitudinal position and second contact pads ofthe second plurality of struts are configured to engage with the bloodvessel wall at a second longitudinal position that is spaced from thefirst longitudinal position.
 6. The blood flow assist system of claim 1,wherein the contact pads are configured to be disposed distal andradially outward of the pump housing and to be reversibly deflectable tohold the pump housing within the blood vessel to hold the pump housingaway from the blood vessel wall.
 7. The blood flow assist system ofclaim 1, wherein the contact pads comprise a convex peripherysurrounding a convex blood vessel engagement surface.
 8. The blood flowassist system of claim 1, wherein the contact pads comprise a convexprofile in a cross-sectional plane disposed transverse to a longitudinalaxis of the pump.
 9. The blood flow assist system of claim 1, whereinthe tether comprises a conductor configured to convey current to a motoroperatively coupled to the impeller from a source connectable to aproximal end of the tether.
 10. The blood flow assist system of claim 9,wherein the pump further comprises a motor housing coupled to a proximalportion of the pump housing, the motor disposed in the motor housing.11. The blood flow assist system of claim 1, wherein the tethercomprises a rotatable drive shaft connected to a motor to be disposedoutside a body of the patient.
 12. A kit comprising the blood flowassist system of claim 1, and a sheath sized and shaped to receive thepump housing, the tether, and the support structure.
 13. A method ofoperating a blood flow assist system, the method comprising: providing apump at a treatment location within a blood vessel of a patient, thepump including a pump housing disposed in a sheath, an impeller disposedin the pump housing, and a tether extending proximally from the pumphousing to outside the patient, the tether configured to oppose loadsapplied in opposite directions at opposite ends thereof; providingrelative motion between the sheath and the pump to remove the pump fromthe sheath; rotating the impeller to pump blood and to generate a thrustforce, wherein a longitudinal component of the thrust force generated bythe impeller directed along a longitudinal axis of the pump is opposedby the tether, the tether configured to maintain a position of the pumpwithin the blood vessel without requiring contact between the pump and ablood vessel wall of the blood vessel.
 14. The method of claim 13,wherein the pump includes a plurality of elongate struts extendingdistally from the pump housing in a collapsed configuration, eachelongate strut of the plurality of struts including a convex contact padat a distal end thereof, wherein providing relative motion comprisescausing the plurality of elongate struts to radially self-expand to anexpanded configuration in which at least one convex contact pad makes atleast intermittent contact with a vessel wall of the blood vessel tomaintain spacing of the pump from the vessel wall.